The present invention is directed to the field of fluid dispense systems. More specifically, the present invention is directed to a single-stroke dispense system for a collapsible dispense container which both provides the fluid to be dispensed and seals the dispense system during dispensement.
The art has seen a variety of dispense systems for delivering a fluid from a storage container to a work surface. Such dispense systems are employed to dispense many types of fluids of varying viscosities. Dispense systems for delivering fluids such as anaerobic adhesives and sealants from a storage container to a work surface may be adversely affected by the curing of the adhesive or sealant while still within the delivery system. As anaerobic adhesives and sealants cure, or harden, in the absence of air, their presence within a fluid delivery system over a period of time can result in their curing within a delivery line between the storage container of the fluid and the dispense port of the delivery system. The problems associated with premature or undesired curing within a delivery system is exacerbated by the use of components, such as valves or conduit, having metallic fluid-contacting components, which require regular maintenance or cleaning. It is well-known in the art to therefore provide delivery systems for anaerobic adhesives and sealants with valve surfaces fabricated from a non-stick surface such as TEFLON(copyright) or DELRIN(copyright). It is also well-known in the art to provide fluid conduit, or tubes, formed from plastics such as TEFLON(copyright), polyethylene, or nylon, which are non-reactive with anaerobic fluids and which are permeable to oxygen so as to supply oxygen to the anaerobic fluid. Employing these materials in an anaerobic fluid delivery system thereby thwarts or delays the fluid from fouling the delivery lines.
Some fluid delivery systems entail reciprocating components having finely designed clearances therebetween for providing mechanical pumping action to move the fluid from a storage container to a dispense nozzle. Small amounts of fluid may become entrapped in these small clearances during the course of normal operation. Such intimate contact between the anaerobic fluid and the dispense system components can, upon the curing of the fluid within the dispense system, disrupt the smooth motion between the components and require time consuming repairs or costly replacement of the reciprocating components. Furthermore, from a dispense operation standpoint, the reciprocating action of these dispense systems produces intermittent dispensement of the fluid at the dispense nozzle. The intermittent dispensement, even when minimized by a short stroke or high frequency piston, provides a non-uniform bead of dispensed material. In many applications, it is desirable to provide as uniform bead of adhesive or sealant at the interface between mating surfaces as possible. It is therefore desirable to provide a single-stroke dispense system for dispensing all of the anaerobic fluid contained within a storage container so as to provide a uniform dispensed bead of fluid and to minimize the exposure of the fluid to any intimate spaces within the dispense system.
The unintended presence of anaerobic fluids within a delivery system is exacerbated by the opening of the fluid storage container prior to placing the container in communication with the dispense system. The problem may also be exacerbated when the storage container is punctured open when initially closing the container within the dispense system. These pre-opened containers increase the likelihood of unintentional fluid spillage or travel within the dispense system, and require increased operator attention and maintenance to limit the risk of the fluid curing within intimate spaces.
It is also common for dispense systems to employ sealing means such as an elastomeric gasket between a storage vessel container body and a storage vessel closure cap. Elastomeric gaskets are susceptible, however, to being contaminated by the material flowing therepast which can result in gasket failure. Gasket deterioration or failure may result in time-consuming and costly maintenance or repair operations. When the gasket is seated within a groove or channel, retrieval of the gasket and cleansing of the channel can be especially time-consuming and difficult. In view of these risks, it is desirable to provide a dispense system for an anaerobic fluid which minimizes or eliminates the need for elastomeric gasket components which may experience long-term exposure to the fluid. It is also desirable to provide a storage container for an aerobic fluid that may be loaded into a dispense system in a sealed condition and that will remain sealed until dispensement is to begin. Furthermore, once dispensement begins, it is desirable for the storage container for the anaerobic fluid to also provide a single-use gasketing means which seals the dispense system throughout dispensement of the fluid from the container.
Certain dispensers of the prior art have utilized a collapsible, rupturable container or bag of fluid within a manually operated dispenser similar to a single stroke air pump. The container, having about 300 milliliters of adhesive or silicone, is placed in a cylindrical housing having a dispense port at one end and a slidable piston which compresses the container about the dispense port. The pressure applied to the container causes the container material to rupture at the dispense port so that continued sliding of the manual piston towards the dispense port expresses the fluid therethrough. Such a manually-operated dispenser is ill-suited to industrial applications due to the small amounts of fluid contained in each container and the recurring need to swap out successive containers in a clean and efficient manner. Furthermore, because the dispense force of the manually-operated piston may be relaxed during intermittent dispensement of the fluid, the fluid is able to back-travel towards the container and leak between the container and the dispenser cavity adjacent the dispense port. Subsequently, removing the container from the cavity of these dispensers is complicated by the entrapped fluid which must be cleared away prior to insertion of subsequent containers or, depending on the fluid, prior to its curing.
For industrial applications, dispense systems of the prior art utilize pressure vessels for storing relatively large quantities of the fluid and for dispensing the fluid pressurizing the pressure vessel. These pressure vessels are typically sealed by mechanical securement means which an operator must properly position and secure so as to maintain the integrity of the pressure vessel when pressurized. The mechanical securement means may include a cap to be threaded over the open end of the pressure vessel or may include, for example, a plurality of threaded clamps which must be individually tightened to abuttingly secure the cap to the pressure vessel. Such mechanical securement means require high manual effort by the operator to ensure that each clamp or threaded fastener is properly torqued so as to sufficiently seal the pressure vessel. An additional drawback to these securement devices is that each may still be unfastened even though the pressure vessel is still pressurized. It would therefore be desirable to provide a sealing system for a pressure vessel that does not require high operator involvement to operate and that provides a fail-safe feature in that the sealing system will prevent pressurized vessel from being opened.
It is therefore desirable to provide a dispense system for a collapsible rupturable container of fluid suitable in industrial settings to dispense large quantities of stored fluid and which provides a clean and efficient swapping out of successive containers of fluid.
The present invention provides a single stroke fluid dispense system, including a dispense member having a dispense end defining a dispense end opening and a container well communicating with the dispense end opening for receiving a fluid to be dispensed. A closure cap is supported over the dispense end opening of the dispense member and further defines a fluid passageway therethrough in fluid communication with the container well. A compression assembly for forcing the fluid through the fluid passageway of the closure cap is also provided. A sealing piston assembly maintains the closure cap in sealing engagement with the dispense member.
The dispense system may include a cap blocking assembly including first and second elongate guide rods extending to either side of the dispense member. Each guide rod includes a first end adjacent the dispense opening of the dispense member. An elongate locking bar is extendable between the first ends of the guide rods across the closure cap opposite the dispense member. A first plate is affixed to the dispense member and supports thereon a plurality of sealing pistons. Each sealing piston includes a sealing piston cylinder and a sealing piston rod extendable and retractable from the sealing piston cylinder. The sealing piston rods are operable against the first and second guide rods to compress the closure cap between the dispense member and the locking bar. A second plate may be fixed with respect to the first and second guide rods for the sealing piston rods to operate against. The second plate may alternatively be affixed to the first guide rod. The second plate defines a centrally-located dispense cylinder passageway therethrough for accommodating the dispense member.
It is contemplated that the dispense member may be formed by an elongate hollow dispense cylinder having an actuation end opposite the dispense end, and an internal cylindrical wall defining an elongate cylindrical passageway therethrough. A hollow internal bushing may be provided to extend into the working end of the dispense cylinder and while being fixed with respect to the first and second guide rods. The internal bushing defines a bushing passageway through which the compression assembly extends.
In place of the second plate, the sealing piston assembly may further include an elongate locking lever pivotally mounted for each sealing piston rod. Each the locking lever includes a first end engaging one the sealing piston rods and a second opposite end engaging one of the first and second guide rods, such that extension of the piston rods against the first ends of the locking levers raises the dispense member against the closure cap.
The locking bar may include a first end pivotally connected to the first guide rod and a second end defining a transversely-extending notch for receiving the second guide rod. Pivoting the locking bar away from the second guide rod allows the closure cap to be removed from its position overlying the dispense opening of the dispense member. Pivoting the locking bar over the closure cap prevents removal of the closure cap from the dispense member.
The compression assembly typically includes an internal piston slidable within the cylindrical passageway of the dispense cylinder. The internal piston supports a piston seal for slidably sealingly engaging the cylindrical wall of the dispense cylinder. A ram apparatus having a main dispense cylinder supports an elongate dispense piston rod which is extendable and retractable from the main dispense cylinder. The dispense piston rod is coupled to the internal piston to extend the internal piston towards the dispense cap upon extension of the dispense piston rod from the main dispense cylinder. The piston seal may be formed of polytretraflouroethylene for ease of dispensing certain adhesives and sealants.
The closure cap may further define a burst port at one end of the fluid passageway facing the container well. The burst port is especially useful for dispensing fluid from a flexible rupturable container. The compression assembly maintains fluid integrity between the container and the closure cap about the rupture port throughout dispensement so as to thwart fluid from leaking into the container well. The container also seals the interface between the dispense member and the closure cap during dispensement of the fluid to be dispensed through the closure cap. As the dispense member is only supported at the dispense end, the compression assembly augments the sealing force between the dispense member and the closure cap by additionally forcing the container against the internal dispense cylinder wall to further carry the dispense cylinder against the closure cap. The present invention is therefore able to augment the sealing force between the dispense member and the closure cap in proportion to the internal pressure generated at the container of fluid.
The dispense member and closure cap of the present invention may therefore include abutting planar annular rims without the need for supporting a sealing or gasket member therebetween. The container for the fluid seals the interface between the dispense member and the closure cap in container-tight engagement, that is, the container will not rupture at the interface of the dispense member and closure cap so that proper dispensement through the burst port is assured. Proper alignment between the dispense member and closure cap may be enhanced by providing a pair of alignment bores and cooperating positioning pins extending between the abutting annular rims of the closure cap and the dispense member.
In one embodiment, the present invention provides a single stroke fluid dispense system for dispensing the contents of a collapsible rupturable plastic container of fluid in which the system includes an elongate hollow dispense cylinder having a dispense end, an actuation end opposite the dispense end, and an internal cylindrical wall defining an elongate cylindrical passage. A closure cap is supported over the dispense end of the dispense cylinder. The closure cap and internal cylindrical wall define a container well for receiving the container of fluid therein. The closure cap further includes a rupture port defining one end of a fluid passageway extending through the closure cap in fluid communication with the container well. An internal piston is mounted for sliding engagement with the internal cylindrical wall and is extendable through the container well. A ram apparatus is operable against the internal piston to move the internal piston towards and away from the closure cap. The dispense system also includes a sealing piston assembly to carry the dispense cylinder against the closure cap in sealing registry over the dispense opening of the dispense member and for freely supporting the working end of the dispense cylinder with respect to the ram apparatus. The ram apparatus also forces the container against the internal dispense cylinder wall to further carry the dispense cylinder against the closure cap. The fluid pressure generated by the ram apparatus within the container well also maintains the fluid integrity between the container and the closure cap about the rupture port throughout dispensement of the fluid. The container itself also seals the interface between the dispense cylinder and the closure cap to maintain the fluid integrity there.